Air-brake accelerator.



No. 766,915. PATENTBD AUG. 9, 1904. V. G. TASKER. AIR BRAKE ACCELERATOR.

APPLICATION FILED 0OT.15, 1903.

H0 MODEL.

able piston J.

.IINiTEn STATES Patented August 9, 1904.

PATENT OEEicE.

VERNON C; TAgKEIt. OF W .ASlE-IINGTHDN, DISITRIOTI OF COLUMBIA, ASSIGNORTO SOOIETE (arENERALE DES FREINS LIPKO'WSKI, OF PARIS, FRANCE,

A FIRM.

AIR-"BRAKE ACCELERATOR.

SPECIFICATION forming" part of Letters Patent No. 766,915, dated August9, 1904.

Application filed October 15, 1903.

To all whom, it ntrty concern.-

Be it known that I, VERNON O. Tasman, a citizen of the United States,residing at Washington. District of Columbia, have invented certain newand useful Improvements in Air- Brake Accelerators, of which thefollowing is a full, clear, and exact description.

The object of the invention is to provide improved means for quicklyexhausting air from the train-pipe under each ear in order to applymaximum-braking effect in case of emergency without appreciable delay inthe transmission of said efiect throughout the train.

In describing the invention in detail referonce will be had to theaccompanying drawings, wherein like characters denote correspondingparts.

Figure 1 is a central vertical section through the acceleratortransverse to the train-pipe, and Fig. 2 is a vertical longitudinalsection through the train-pipe and a portion of the accelerator alongthe line 2 2 of Fig. 1.

In the drawings, A is a casing having at its lower extremity alongitudinal chamber B in line with the train-pipe T and communicatingtherewith. In said chamber B is a perforated hollow cylinder 1). servingas an airstrainer and registering with the train-pipe, being centered atE and F and secured against endwise movement by a flange (ii.

A branch pipe U from the bottom of the chamber B communicates with atriple valve (not shown) to actuate the brakes. The chamber B thuscorresponds in a general way with the usual car drain-cup.

Aside from chamber B the casing A is situated entirely above the trainpipe, the better to drain the parts therein and prevent accumulation ofdrip from the train-pipe. The

said upper part of easing A is divided into two compartments by thehorizontally-mov- One of said compartments, K, forms an air-reservoirclosed by the cap M and gasket N and communicates solely through thesmall perforation O with the other compartment, L, which in turncommunicates freely with the train-pipe. The piston J has an axialprolongation P of star-shaped cross- Serial No. 177,157. (No model.)

section (see Fig. 2) extending through the compartment L and easing Aand guided by a cylindrical bushing Q in the latter.

l\ZIOUDt6Cl upon the stem 1t, integral with the piston J and secured bythe nut S, is a valve washer or gasket V. adapted to seat in wardlyagainst bushing Q. A helical spring WV acting against the piston J tendsto keep the valve V lirmly seated.

During an ordinary application of the brakes the reduction of pressurein the trainpipe is so light as to permit of equalization of pressure onthe two sides of the piston through the port O without moving saidpiston or unseating valve V. In an emergency application, however,brought about by a sudden great .reduetion of train-pipe pressure thepreponderance of pressure in reservoir K is sufficient to instantly movepiston J the full extent of its travel and Furnish an additionalexhaustqmssage by the valve V. The

reduction of train-pipe pressure thus brought about causes theaccelerator next behind in the train to act and so on in like mannerthroughout the train, so that the maximum braking efl'ect is instantlytransmitted throughout the length of the train.

Among the advantages of the form 01' exhaust-valve V here shown are itsfreedom from the numerous disadvantages of a slidevalve, its greatventage oi air for given piston travel, and. the fact that it begins toexhaust at the same instant that the piston J begins to move.

It will be also noted that by the combination and arrangement of partshere shown I am enabled to m'ovide anel'lieient, durable, andwell-drained accelerating apparatus without in the slightest degreeobstructing the flow of the column of air in the train-pipe.

Having thus described my invention, what I claim. and desire to secureby Letters Patent of the United States, is-- 1. An accelerator forair-brakes comprising a casing containing a suitably-drainedairreservoir, a horizontally-movable piston communicating therewith andhaving an axial stem of star-shaped cross-section extending andexhaust-valve outlet-chamber in horizonzontally-rnovable piston therein,an exhausttal sequence, a drain-plug for said reservoir. and a drain-cupbelow said piston-cylinder and exhaust-valve chamber, adapted to drainthe same and also serving to communicate with the triple valve andpermit free passage of train-pipe air, substantially as described.

3. An accelerator for air-brakes comprising a clear passage in line withthe train-pipe, a piston-chamber above said passage, a horioutletcommunicating with said piston-chamber and train-pipe passage, aninwardly-seating puppet-valve for said exhaust-outlet carried by saidpiston, a spring tending to keep said valve normally seated, and anair-reservoir on the opposite side of the piston, sub stantially as andfor the purpose described.

a. An accelerator for air-brakes comprising a clear passage in line withthe train-pipe, a pistonchamber above said passage, ahorizontally-movable piston therein, an exhaustoutlet fitted with aninwardly-seating puppetvalve carried by said piston, a spring normallytending to seat said valve, and an airreservoir on the opposite side ofsaid piston, substantially as and for the purposes described. I

5. An accelerator for air-brakes having the air reservoir, pistoncylinder and exhaustvalve chamber in horizontal sequence, and adrain-cup below said exhaust-valve chamber, said drain -cup affordingunobstructed passage for train-pipe air and provided with anair-strainer.

In testimony whereof I have signed my name to this specification inpresence of two witnesses.

VERNON o. TASKER.

lVitnesses:

W. F. Ron, A. Y. LEECH, Jr.

